Search found 103 matches

by Jason S
2011-12-04T14:14:48-07:00
Forum: Users
Topic: Emulating a resize algorithm
Replies: 2
Views: 5648

Re: Emulating a resize algorithm

I figured out a way to make the box filter work. I'd assumed I could distort both dimensions at once, but it only works if I separate them. convert Rings1.gif \ -filter box -define filter:blur=0.707 \ +distort SRT "0,0 0.8,1.0 0 0.3999,0.0" -crop 800x1000+0+0 \ +distort SRT "0,0 1.0,0.8 0 0.0,0.3999...
by Jason S
2011-12-04T07:52:20-07:00
Forum: Users
Topic: Emulating a resize algorithm
Replies: 2
Views: 5648

Emulating a resize algorithm

I worked out most of the details about how Photoshop resizes images ( link ). For no particular reason, I want to see if ImageMagick can be made to resize images in the same way. There are two things I still need: 1. A way to apply a box filter that also translates the image by a fraction of a pixel...
by Jason S
2011-11-09T19:38:31-07:00
Forum: Digital Image Processing
Topic: How to identify a resampling filter
Replies: 4
Views: 16433

Re: How to identify a resampling filter

Oh, I definitely know about most of the things you're talking about. (Lagrange filters are an exception, maybe -- I know what they look like, but don't know the theory.) There are indeed a lot of ways to get tripped up. I've found many of them by accident :). I do plan to make some sort of a tutoria...
by Jason S
2011-11-08T17:52:47-07:00
Forum: Digital Image Processing
Topic: How to identify a resampling filter
Replies: 4
Views: 16433

How to identify a resampling filter

I'm interested in evaluating applications to figure out what image scaling algorithms they use, and how well those algorithms are implemented. So, I'm working on a little utility to help do that. It uses strategically-designed source images that you resize, then use it to analyze. In part, it does w...
by Jason S
2011-10-29T11:09:11-07:00
Forum: Bugs
Topic: IM may write GIF files with an invalid image position
Replies: 4
Views: 9087

IM may write GIF files with an invalid image position

(from this thread ) This command convert rose: -units PixelsPerInch -density 100x100 -page 70x46+100+100 test1.gif write a GIF image with a logical screen size of 70x46, containing a single image of size 70x46, which is positioned at offset +100+100. The GIF89a specification says "Each image must fi...
by Jason S
2011-10-29T11:03:24-07:00
Forum: Users
Topic: surreal problems import-ing in GIF format
Replies: 9
Views: 16660

Re: surreal problems import-ing in GIF format

alexxx wrote:So you don't think I should file it as a bug?
It's not a bug. I was wrong about it defaulting to inches. Provided the XResolution and YResolution tags are present, the position can always be translated to pixels, regardless of whether the units are specified.
by Jason S
2011-10-27T08:27:02-07:00
Forum: Users
Topic: surreal problems import-ing in GIF format
Replies: 9
Views: 16660

Re: surreal problems import-ing in GIF format

Apparently, "+repage" is the way to fix this.

Code: Select all

convert f.gif +repage f3.gif
I'm having second thoughts about calling the ResolutionUnit issue a bug. While it doesn't seem quite right, there's no obvious solution, and it might be the most reasonable behavior.
by Jason S
2011-10-27T07:42:27-07:00
Forum: Users
Topic: surreal problems import-ing in GIF format
Replies: 9
Views: 16660

Re: surreal problems import-ing in GIF format

ImageMagick is trying to be clever, and keep track of an image position within a logical screen. There's probably a way to tell it not to do that -- maybe someone else can help. Also... Your f2.gif is not a valid GIF file. The GIF89a spec says: Each image must fit within the boundaries of the Logica...
by Jason S
2011-10-10T17:36:41-07:00
Forum: Bugs
Topic: identify does not correctly detect iptc encoding
Replies: 13
Views: 31651

Re: identify does not correctly detect iptc encoding

I'm curious as to how it could have worked in old versions (but not curious enough to spend the time to figure it out). The real solution to this, and lots of similar problems, is straightforward. Maybe it's time to start pushing for it to happen. 1. Put stdout in Unicode mode. 2. Convert all human-...
by Jason S
2011-09-22T18:39:27-07:00
Forum: Bugs
Topic: Bug with @{file_name} attribute and convert
Replies: 3
Views: 7944

Re: Bug with @{file_name} attribute and convert

Just wondering if there's a plan to fix this, and similar problems. Since I'm partly responsible for the update that broke it, I feel like I should lobby for it. I was able to fix this particular issue with a patch like this: #if defined(MAGICKCORE_HAVE__WFOPEN) int open_utf8(const char *filenameUTF...
by Jason S
2011-09-21T08:25:37-07:00
Forum: Developers
Topic: Static Linking
Replies: 13
Views: 34038

Re: Static Linking

Of course, you need a static version (.a file) of any library that you're going to statically link to. If you can't get a static libtiff (etc.) from the same source as your shared libtiff, you'll have to build one yourself. That's usually not very hard, but you may need to be careful about how you c...
by Jason S
2011-09-15T11:32:29-07:00
Forum: Bugs
Topic: Bug with @{file_name} attribute and convert
Replies: 3
Views: 7944

Re: Bug with @{file_name} attribute and convert

I think the bug is in the FileToBlob function in magick/blob.c. On Windows, instead of calling open(), the parameters need to be converted from UTF-8 to UTF-16, and passed to _wopen() instead. Note that the problem that caused you to do it this way has been fixed. You can now use arbitrary character...
by Jason S
2011-09-15T07:42:31-07:00
Forum: Bugs
Topic: problem when using ordered dithering
Replies: 1
Views: 4881

Re: problem when using ordered dithering

What version of ImageMagick are you using? This bug does exist in old versions, but I can't reproduce it with v6.7.2-4.
by Jason S
2011-09-10T16:17:35-07:00
Forum: Developers
Topic: Static Linking
Replies: 13
Views: 34038

Re: Static Linking

I assume that what you want is for the ImageMagick utilities like convert and identify to be static executables. I don't know any way to do that, that isn't a hack. After you run configure , try editing Makefile , and appending "-all-static" to the line that starts with "LDFLAGS =". That will cause ...
by Jason S
2011-09-04T17:15:59-07:00
Forum: Bugs
Topic: Bilevel tif annotate
Replies: 15
Views: 29745

Re: Bilevel tif annotate

The logo_tmp2.tif file I got was LZW-compressed, with a 1-bit black/white channel and a 1-bit alpha channel. This is an arguably-valid TIFF image, but application support for it is very low.

If you know you don't need transparency, doing something to remove it (e.g. "+matte") should help.